Product placement in movies and TV shows – whether subtle or more obvious – can expose a product to millions of people, and in a situation and use that is most positive to the brand.

Celebrity sponsorships – from sports to musicians to “constructed celebrities” like Paris Hilton and the Kardashians (a name that I just found out is in my spellcheck dictionary) – can have spectacular impact on the sponsoring company, just ask Nike how valuable their relationship with Michael Jordan is.

Even a 140 character tweet (paid or from the heart) from someone you follow can trigger the exploration and/or purchase of just about anything. Or, in a less material slant, support of a cause or individual.

What all of these tactics have in common is the power of influence. More and more, what your friends – real or “I know we’d be BFFs if we ever met” – feel, think, know, or do influences what you feel, think, know, or do.

And it can cut both ways.

A simple comment about what’s wrong with a product, how the experience went bad, or even a whimsical slam can have a negative impact to the same degree as the positive.

This type of influence is not exclusive to purchases or opinions. It can, and does, expand to culture and actions of other kinds.

Researchers looking to explain suicide clusters – an abnormal number of suicides in a given community or area – found that the actions of an individual or two can trigger a “copycat syndrome” where others who may have never truly contemplated suicide are drawn to do so.

The speed at which a single incident can become a more common occurrence is something to watch carefully and be conscious of. In the one month after Marilyn Monroe’s suicide there were 200 more suicides than average. This is part of the reason that there was criticism of the way some looked to celebrate Robin Williams at the time of his suicide.

A “flywheel” effect can take place, where the energy from a small beginning builds on itself to become much bigger. The phenomenon of “flash crashes” in financial markets issimilar – where one action triggers an ever-building set of actions, often computer trades based on specific price or data levels.

This increasing speed, influence, and reach – both good and bad – is one way that the fringe or Black Swans (something unthinkable because it’s never been seen, but none the less is very real) have Janus Moments and become the norm.